Search

The addition of a third anti-malarial drug matching the pharmacokinetic characteristics of the slowly eliminated partner drug in artemisinin-based combination therapy (ACT) has been proposed as new therapeutic paradigm for the treatment of uncomplicated falciparum malaria. These triple artemisinin-based combination therapy (TACT) should in theory more effectively prevent the development and spread of multidrug resistance than current ACT. Several clinical trials evaluating TACT-or other multidrug anti-malarial combination therapy (MDACT)-have been reported and more are underway. From a regulatory perspective, these clinical development programmes face a strategic dilemma: pivotal clinical trials evaluating TACT are designed to test for non-inferiority of efficacy compared to standard ACT as primary endpoint. While meeting the endpoint of non-inferior efficacy, TACT are consistently associated with a slightly higher frequency of adverse drug reactions than currently used ACT. Moreover, the prevention of the selection of specific drug resistance-one of the main reasons for TACT development-is beyond the scope of even large-scale clinical trials. This raises important questions: if equal efficacy is combined with poorer tolerability, how can then the actual benefit of these drug combinations be demonstrated? How should clinical development plans be conceived to provide objective evidence for or against an improved management of patients and effective prevention of anti-malarial drug resistance by TACT? What are the objective criteria to ultimately convince regulators to approve these new products? In this Opinion paper, the authors discuss the challenges for the clinical development of triple and multidrug anti-malarial combination therapies and the hard choices that need to be taken in the further clinical evaluation and future implementation of this new treatment paradigm.

Background: Benefits of mobile phone deployment for children

The cytokine profile of CD4+, CD8+ T cells, gammadelta+ T cells and natural killer (NK) cells (CD94+CD3-) was studied in a patient with visceral leishmaniasis (VL). The otherwise healthy, human immunodeficiency virus-negative patient acquired the disease in Tuscany, Italy. Diagnosis was made by demonstration of high concentrations of antibodies against Leishmania antigens in serum. Flow cytometry for the detection of intracellular interferon-gamma (IFN-gamma), interleukin (IL)-2, IL-4, IL-6, IL-10, IL-13 and tumour necrosis factor (TNF)-alpha expression in peripheral blood mononuclear cells stimulated with phorbol 12-myristate 13-acetate and ionomycin was performed, followed by treatment with liposomal amphotericin B. CD4+ cells were identified as major cytokine-expressing cells, capable of producing both type 1 and type 2 cytokines. A high frequency of IL-4- and IL-13-expressing CD8+ cells was noted. NK cells and gammadelta+ T cells, thought to be involved in innate host defences against Leishmania, expressed IFN-gamma and TNF-alpha. Ten per cent of gammadelta+ T cells expressed IL-10, predominantly together with IFN-gamma, suggesting additional immune-regulatory roles for this T-cell subset in VL.